Through the Scope Tension Member Release Clip

ABSTRACT

An apparatus for deployment of a hemostatic clip comprises a handle assembly, a shaft connected to a distal portion thereof and a clip assembly releasably coupled to a distal portion of the shaft. The clip assembly includes clip arms and a capsule cooperating with the clip arms to provide a first user feedback indicating a decision configuration of the clip assembly. In addition, the apparatus includes a control wire including a ball connector, the control wire extending from the handle assembly and coupled to the clip assembly by the ball connector to maintain the clip assembly coupled to the shaft, wherein the ball connector is detachable from the clip assembly to provide a second user feedback indicating separation of the clip assembly from the shaft.

PRIORITY INFORMATION

The present application is a Continuation of pending U.S. patentapplication Ser. No. 13/303,802 filed on Nov. 23, 2011, now U.S. Pat.No. 8,915,837; which is a Continuation of U.S. patent application Ser.No. 12/362,610 filed on Jan. 30, 2009, now U.S. Pat. No. 8,088,061;which is a Continuation of U.S. patent application Ser. No. 10/674,512filed on Sep. 30, 2003, now U.S. Pat. No. 7,494,461. The entiredisclosure of the above patents/applications is expressly incorporatedherein by reference.

BACKGROUND

Endoscopic procedures to treat abnormal pathologies of thegastro-intestinal (“GI”) canal system, of the biliary tree, of thevascular system and of various other body lumens are becomingincreasingly common. The endoscope is basically a hollow tube that isplaced at a desired location within the body to facilitate access to therelevant body ducts and lumens, etc. The endoscope itself cannot carryout many of the required procedures. To that end, the endoscope isfitted with a lumen, or internal channel, which permits the user toinsert various medical devices therethrough to the location thatrequires treatment. Once the distal end of the inserted device hasreached the tissue to be treated, it can be manipulated using controlswhich remain outside the body.

An hemostatic clipping tool is one of the devices which may be insertedthrough an endoscope so that treatment may be carried out. Hemostaticclips are deployed from the clipping tool and are used to stop internalbleeding by clamping together the edges of a wound. The clipping toolcomplete with clips attached to its distal end is inserted through theendoscope to the location of the bleeding. A clip is then remotelymanipulated into position over the site of bleeding, clamped over thewound and detached from the tool. After a number of clips sufficient tostop the bleeding has been deployed, the tool is withdrawn from thepatient's body through the endoscope. The size and shape of the clipsand of the clipping tool are limited by the inner diameter of theendoscope's lumen, thus placing constraints on the design of the clippositioning and release mechanisms.

One challenge facing the endoscope operator is to properly position thehemostatic clips over the wound, so that closing the clips over thetissue will be effective in stopping the bleeding. If a clip is deployedimproperly, additional clips may be required to stop the bleedingextending the time required for and the complexity of the procedure andleaving additional medical devices within the patient. It is alsoimportant for the device operator to be certain of the status of theclip during the deployment operation. For example, before withdrawingthe tool from the endoscope, the operator should have positiveindication that a clip has fully deployed, and has been released fromthe tool. At the same time the design of the tool should ensure thatclips are fully released after they have been closed over the tissue.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to an apparatus fordeployment of a hemostatic clip comprising a handle assembly and a shaftconnected to a distal portion of the handle assembly in combination witha clip assembly releasably coupled to a distal portion of the shaft, theclip assembly including clip arms and a capsule cooperating with theclip arms to provide a first user feedback indicating a decisionconfiguration of the clip assembly and a control wire including a ballconnector, the control wire extending from the handle assembly andcoupled to the clip assembly by the ball connector to maintain the clipassembly coupled to the shaft, wherein the ball connector is detachablefrom the clip assembly to provide a second user feedback indicatingseparation of the clip assembly from the shaft.

In a different aspect, the present invention is directed to a clipassembly deployable through an endoscope, comprising a capsulereleasably connected to a bushing of an elongated clip deploymentdevice, clip arms slidable within the capsule between a distal openconfiguration and a proximal closed configuration, a tension memberslidable with the clip arms, urging the clip arms in the openconfiguration, and a yoke slidable within the capsule, releasablyconnected to the tension member at one end, and connected to a controlwire of the clip deployment device at another end. In the invention,distal movement of the control wire slides the clip arms in the openconfiguration, and proximal movement of the control wire slides the cliparms in the closed configuration.

In a further embodiment, the invention is directed to a method forhemostatic clipping through an endoscope. The method includes providinga shaft section connected to a clip assembly of a clipping deviceinsertable through an endoscope working lumen, providing a handleassembly attached to the shaft section, the handle assembly allowinglongitudinal movement of a control wire, and providing a connectionbetween a distal end of the control wire and clip arms of the clipassembly, whereby longitudinal movement of the control wire moves theclip arms between an open and a closed configuration. The method alsoincludes giving a first user feedback indicating a decisionconfiguration of the clip assembly, and giving a second user feedbackindicating separation of the clip assembly from the shaft section.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a schematic side view of a clipping device according to anembodiment of the present invention, with a detail view of an exemplaryclip assembly;

FIG. 1 b shows a detailed view of a clip assembly shown in FIG. 1 a;

FIG. 2 is a schematic side view of the embodiment shown in FIG. 1 a,with a outer sheath;

FIG. 3 is a cut away side view of the shaft section according to anembodiment of the present invention;

FIG. 4 is a cross sectional view of the shaft section shown in FIG. 3;

FIG. 5 is a detail view of the distal end of the control wire accordingto an embodiment of the present invention;

FIG. 6 is a perspective view of an outer sheath according to anembodiment of the present invention;

FIG. 7 is an cross sectional exploded view of the handle of the outersheath shown in FIG. 6;

FIG. 8 is a perspective view of an outer sheath lock according to anembodiment of the present invention;

FIG. 9 is a cross sectional side view of a distal end of a clippingdevice according to an embodiment of the present invention;

FIG. 10 is a cross sectional top view of a distal end of the clippingdevice shown in FIG. 9;

FIG. 11 is a perspective view of the distal end of the clipping deviceshown in FIG. 9;

FIG. 12 is a top view of the clip arms according to an embodiment of thepresent invention;

FIG. 13 is a perspective view of the clip arms shown in FIG. 12,according to an embodiment of the present invention;

FIG. 14 is a perspective view of a capsule according to an embodiment ofthe present invention;

FIG. 15 is a cross sectional side view of the of the capsule shown inFIG. 14;

FIG. 16 is a top view of the distal end of a clipping device accordingto an embodiment of the present invention;

FIG. 17 is a side view of the distal end shown in FIG. 16;

FIG. 18 is a perspective view of a clip arm according to an embodimentof the present invention;

FIG. 19 is a side view of the clip arm shown in FIG. 18;

FIG. 20 is a top view of the clip arm shown in FIG. 18;

FIG. 21 is a perspective view of a bushing according to an embodiment ofthe present invention;

FIG. 22 is a cross sectional side view of the bushing shown in FIG. 21;

FIG. 23 is a perspective view of a wire stop according to an embodimentof the present invention;

FIG. 24 is a schematic side view of a clip assembly detached from abushing, according to an embodiment of the present invention;

FIG. 25 is a side view of a tension member according to an embodiment ofthe present invention;

FIG. 26 is a top view of the tension member shown in FIG. 25;

FIG. 27 is a top view of a yoke according to an embodiment of thepresent invention;

FIG. 28 is a perspective view of the yoke shown in FIG. 27; and

FIG. 29 is a top view of a yoke with a control wire according to anembodiment of the present invention.

DETAILED DESCRIPTION

Hemostatic clips are used routinely to stop bleeding from openingscreated during surgery as well as wounds resulting from other trauma totissues. In the simplest form, these clips grasp the tissue surroundinga wound and bring the wound's edges together, to allow the naturalscarring process to heal the wound. In endoscopic hemostatic clips areused to stop internal bleeding due resulting from surgical proceduresand/or tissue damage from disease, etc. Specialized endoscopichemostatic clipping devices are used to bring the clips to the desiredlocation within a patient's body and to position and deploy the clip atthe appropriate place on the tissue. The clipping device is thenwithdrawn, leaving the clip within the patient.

Endoscopic hemostatic clipping devices are designed to reach affectedtissues deep within a patient's body, such as within the GI tract, thepulmonary system, the vascular system or within other lumens and ducts.During the procedures to treat those areas, an endoscope is generallyused to provide access to and visualization of the tissue which is to betreated. The clipping device may, for example, be introduced through aworking lumen of the endoscope. The design and construction of such a“through the scope” endoscopic hemostatic clipping device presentsseveral challenges. The endoscopic clipping device has to besufficiently small to fit in the lumen of an endoscope and, at the sametime, must be designed to provide for the positive placement andactuation of the hemostatic clip. Feedback to the operator is preferablyalso provided so that the operator will not be confused as to whetherthe hemostatic clip has been properly locked in place on the tissue andreleased from the device before the device itself is withdrawn throughthe endoscope.

FIG. 1 a shows a side elevation view of a through the scope hemostaticclipping device according to an exemplary embodiment of the presentinvention. This device is a hand operated tool that is used to insert ahemostatic clip through an endoscope lumen, position the clip over awound, clamp it and deploy it over the affected tissue. The tool isfurther designed to release the hemostatic clip once it has been clampedin place, and to be withdrawn through the endoscope. To more clearlyexplain the operation and construction of the exemplary device, it maybe divided into three principal components. As shown, the hemostaticclipping device 100 comprises a handle assembly 102, a shaft section104, and a clip assembly 106. The clip assembly 106 is shown moreclearly in the detail A depicted in FIG. 1 a, as shown in FIG. 1 b.

Handle assembly 102 forms the component that supplies a mechanicalactuation force to deploy and clamp the clip. In this embodiment, thedevice is hand operated (i.e., the user's hands provide the forcerequired to carry out all the functions related to the hemostatic clip).The handle assembly 102 may be constructed in a manner similar toconventional handle assemblies of the type generally employed inendoscopic biopsy devices or in similar applications. The handleassembly 102 allows the user to move a control wire 118 or other forcetransmission member, which extends through the shaft section 104 to theclip assembly 106 at a distal end of the device 100. The handle assembly102 comprises a handle body 108 which can be grasped by the user tostabilize the device and apply a force to it. A sliding spool 110 isconnected to control wire 118, so that the user can easily pull or pushsaid wire 106 as desired.

As shown in FIGS. 1 a and 2, a sliding spool 110 is mounted on thehandle body 108 so that it can slide along a slot 116, which maintainsits position within the handle assembly 102. Because the sliding spool110 is connected to the control wire 118, the user may manipulate thecontrol wire 118 by grasping the handle body 108 and moving the slidingspool 110 along the slot 116. A return spring 112 may be provided withinthe handle body 108 to bias the sliding spool 110, and thus the controlwire 118 toward a desired position. In the present embodiment, thesliding spool 110 is biased to the proximal position. The handleassembly 102 may also include a connection portion 114, which receivesthe control wire 118 and attaches the shaft section 104 to the handleassembly 102.

The shaft section 104 mechanically connects the handle assembly 102 tothe clip assembly 106 and, together with the clip assembly 106, isdesigned to be inserted into a lumen of an endoscope. As shown in FIGS.3 and 4, the shaft section 104 comprises an outer flexible coil 130which is designed to transmit a torque from the proximal end to thedistal end of the device 100 and to provide structural strength to theshaft section 104. The coil 130 may be a conventional coil used inbiopsy devices and may, for example, comprise a single, coiled wire. Thecoiled wire may have a round, square or a rectangular cross section, andmay be made of a biocompatible material such as, for example, stainlesssteel. Additional protective and low friction outer layers may beincluded on the shaft section 104, according to known methods ofconstruction.

The control wire 118 transmits mechanical force applied to the handle102 to the clip assembly 106. The control wire 118 has a proximal endwhich is attached to a movable part of the handle 102, such as thesliding spool 110, using known methods. Stainless steel or other highyield biocompatible materials may be used to manufacture the controlwire 118, so that the structural integrity of the assembly ismaintained. It is also important to prevent stretching of the controlwire 118 when under tension since, if the wire stretches, the handle 102will have to travel a greater distance to carry out a desired operation.As shown in FIG. 5, the distal end of the control wire 118 ends in aball 140 which is used to connect the control wire 118 to theappropriate elements of the clip assembly 106, as will be describedbelow. In this embodiment, the diameter of the control wire 118 issubstantially constant from a proximal end thereof to a proximal end ofa distal tapered section 144. The ball 140 may have a diameter which isgreater than the diameter of the control wire 118, to facilitateattachment to a yoke 204. The control wire 118 may extend the length ofthe device 100, from the yoke 204 to the sliding spool 110, and slideslongitudinally through the device 100. It may be made, for example, ofstainless steel or other biocompatible metal.

The control wire 118 may also include a reduced diameter section 142designed to fail when a predetermined tension is applied thereto throughthe handle assembly 102. The tapered section 144 may be used totransition between the main body of the control wire 118 and the reduceddiameter section 142, without steps or other discontinuities which mayconcentrate stress and make the fracture point more unpredictable. Aswill be described in greater detail below, one purpose of the reduceddiameter section 142 is to facilitate the release of a hemostatic clipfrom the hemostatic clipping device 100 once the clip has been properlydeployed. It will be apparent to those of skill in the art that thelocation of the reduced diameter section 142 the along control wire 118may be varied to take into account specific requirements of the device100.

An inner sheath 132 may be used in the construction of the shaft section104, as shown in FIGS. 3 and 4. The inner sheath 132 provides a lowfriction bearing surface disposed between the outer diameter of thecontrol wire 118, and the inner diameter of the shaft section 104. Theinner sheath 132 may be formed of a low friction material such as, forexample, Teflon™, HDPE or Polypropylene. In one exemplary embodiment,the inner sheath 132 is slidable within the shaft section 104, and thecontrol wire 118 is slidable within the inner sheath 132 forming a lowfriction system of multiple bearing surfaces. To further reducefriction, a bio-compatible lubricant may be applied to the inner andouter surfaces of the inner sheath 132, along the length of the shaftsection 104. For example, silicone lubricants may be used for thispurpose.

A slidable over-sheath 150 may be included in the design of the shaftsection 104, as shown in FIGS. 1 a and 2. The over-sheath 150 isdesigned to protect the inner lumen of the endoscope from the metal clipassembly 106 and from the metal coil 130 while the hemostatic clippingdevice 100 passes through the endoscope's lumen. After the clippingdevice 100 and, more specifically, after the clip assembly 106 haspassed through the endoscope, the over-sheath 150 may be withdrawn toexpose the distal portion of the clipping device 100. The over-sheath150 may be formed, for example, as a single lumen plastic extrusionelement slidable over the distal portions of the clipping device 100 toselectively cover and uncover the clip assembly 106. In one embodiment,the over-sheath 150 is formed of a low friction polymer such as, forexample, Teflon™, HDPE, Polypropylene, or similar materials.

The over-sheath 150 may include a grip portion 152 and an elongated body154. The grip portion 152 is designed as a handle making it easier forthe user to slide the over-sheath 150 over the shaft of the clippingdevice 100. In one exemplary embodiment, the grip portion 152 is made ofa rubber-like material to provide a good gripping surface for the user.For example, an injection moldable polymer such as TPE may be used toconstruct the grip portion 152. The elongated body 154 may be formed asa substantially cylindrical shell surrounding the shaft of the clippingdevice 100. The elongated body 154 may be attached to the grip portion152 using conventional methods as would be understood by those skilledin the art.

As shown in FIGS. 6 and 7, an exemplary grip portion 152 comprises acentral hollow channel 160 that may be used to receive the shaft of theclipping device 100. The central hollow channel 160 is aligned with theelongated body 154 to provide a continuous channel containing the shaftof the clipping device 100. The material of the grip portion 152 mayhave a high coefficient of friction, so that an interference fit ispossible between the central hollow channel 160 and the shaft of theclipping device 100 without the use of adhesives or mechanical fasteningdevices. In one embodiment, friction bosses 158 may be provided on aninner diameter of the hollow channel 160 to provide additional frictionbetween the shaft of the clipping device 100 and the over-sheath 150assembly. The friction bosses 158 may be formed, for example, asprotrusions extending from the inner diameter of the over-sheath 150 andmay have a variety of stubby or elongated shapes. The amount of frictionbetween these two components may be balanced so that no unwantedrelative movement takes place while, at the same time, making itrelatively easy for the user to slide the over-sheath 150 proximally anddistally when necessary.

A sheath stop 156 may be provided for the clipping device 100 to preventthe over-sheath 150 from sliding away from the distal end while theclipping device 100 is inserted in the endoscope. As shown in theexemplary embodiment of FIGS. 2 and 8, the sheath stop 156 physicallyblocks the grip portion 152 from sliding proximally to prevent theover-sheath 150 from being withdrawn and exposing the clip assembly 106.The sheath stop 156 is designed to easily snap in place near theproximal end of the shaft section 104 where it can be reached andmanipulated by the operator during the surgical procedure. Once the clipassembly 106 has been inserted in the endoscope and has reached thedesired location in the patient's body, the sheath stop 156 may beremoved from the shaft section 104 so that the user can move the gripportion 152 proximally to uncover the clip assembly 106.

The connection between the sheath stop 156 and the shaft section 104 mayinclude, for example, pairs of opposing fingers 162, 164 that aredesigned to snap over the shaft section 104. The fingers 162, 164cooperate to securely and releasably hold the body of the shaft section104 therebetween. The fingers 162, 164 respectively comprise guideportions 170, 172; shaft channel portions 166, 168; and blockingportions 174, 176. Insertion of the sheath stop 156 on the elongatedbody 154 is accomplished by pressing the body of the shaft section 104between the guide portions 170, 172, to spread the fingers 162, 164 andallow further insertion of the shaft 104 between the fingers 162, 164.The guide portions 170, 172 and the blocking portions 174, 176 areshaped so that insertion of the shaft section 104 towards the channelportions 166, 168 requires less effort than moving the shaft section 104in the opposite direction.

Once shaft section 104 has been placed within the channel portions 166,168, the fingers 162, 164 snap back to their non-spread position andretain the shaft section 104 in place therebetween. The shaft section104 is removed by pulling the sheath stop 156 away from the shaftsection 104. Due to the shape of the blocking portions 174, 176,removing the shaft section 104 requires the application of more forcethan does insertion thereinto. Stops 180 may also be provided on thesheath stop 156 to limit the movement of the shaft section 104 towardsthe grasping portion 161 to prevent damage to the device that may becaused by excessive spreading of the fingers 162, 164. The sheath stop156 may be formed of a resilient material, such as a polymer, and may bemanufactured by injection molding.

The clip assembly 106 is disposed at the distal end of the clippingdevice 100, and contains the mechanism that converts the proximal anddistal movement of the control wire 118 into the actions necessary todeploy and release a hemostatic clip 90. FIGS. 9, 10 and 11 show,respectively, side, top and perspective views of the distal end of theclipping device 100, including the clip assembly 106 having clips in thefolded configuration. This configuration is used, for example, to shipthe clipping device 100 and to insert the clipping device 100 throughthe lumen of an endoscope. Some of the components of the clip assembly106 include a capsule 200 which provides a structural shell for the clipassembly 106, the clip arms 208 which move between open and closedpositions, a bushing 202 attached to the distal end of the control wire118, and a yoke 204 adapted to connect the capsule 200 to the controlwire 118.

As depicted, the proximal end of the capsule 200 slides over the distalend of the bushing 202. A locking arrangement between these twocomponents is provided by capsule tabs 212, which are designed to lockinto the bushing 202 so that mechanical integrity is temporarilymaintained between the capsule 200 and the bushing 202. Within thecapsule 200 are contained a yoke 204 and a tension member 206 whichtransmit forces applied by the control wire 118 to the clip arms 208.The ball 140 formed at the distal end of the control wire 118 is matedto a receiving socket 210 formed at the proximal end of the yoke 204. Amale C-section 214 extending from the tension member 206 is received ina corresponding female C-section 216 formed in the yoke 204, so that thetwo components are releasably connected to one another, as will bedescribed below. The clip arms 208 in the closed configuration have aradius section 300 which is partially contained within the capsule 200to prevent opening of the arms. Each of the clip arms 208 goes over thetension member 206 and has a proximal end 222 which slips under a yokeoverhang 254, to further control movement of the arms 208.

FIGS. 12 and 13 show a top and a perspective view of the clip assembly106 in an open configuration with the clip arms 208 in a fully openposition. The open configuration is obtained when the sliding spool 110shown in FIG. 1 a is moved distally so that the ball 140 of the controlwire 118 pushes the assembly containing the yoke 204 and the tensionmember 206 forward, sliding within the capsule 200. As will be describedbelow, the distal ends of the clip arms 208 are biased toward the openposition and revert to this position whenever they are not constrainedby the capsule 200. In the exemplary embodiment, a maximum opening ofthe clip arms 208 occurs when the clip arms 208 ride over the foldeddistal folding tabs 220 which extend from the distal end of the capsule200, as shown in FIGS. 14 and 15. In this embodiment, the tabs 220provide a cam surface, and the clip arms 208 act as cam followers, beingdeflected by the tabs 220. In addition, the folding tabs 220 may alsoprovide a distal stop for the tension member 206, to retain it withinthe capsule 200. Thus, by moving the sliding spool 110 distally, theuser opens the clip arms 208 to prepare to grasp tissue therebetween.

When the sliding spool 110 is moved proximally by the user, the assemblywithin the capsule 200 also moves proximally and the clip arms 208 arewithdrawn within the capsule 200. As the clip arms 208 move proximallywithin the capsule 200, clip stop shoulders (CSS) 222 contact a distalportion of the capsule 200, for example, the folded tabs 220. Thisinteraction of the CSS 222 with the capsule 200 provides to the user afirst tactile feedback in the form of increased resistance to movementof the sliding spool 110. This feedback gives to the operator a positiveindication that further movement of the handle control will cause thehemostatic clip 90 to be deployed from the clip assembly 106. Theoperator may then decide whether the current position of the clip 90 isacceptable or not. If the position is acceptable, the operator candeploy the clip 90 by continuing to move the sliding spool 110 withincreased proximal pressure to cause the clip arms 208 to close on thetissue. If not, the operator can move the sliding spool 110 distally tore-open the clip arms 208 and extend them out of the capsule 200,reposition the clip 90, and repeat the above steps to close the clip 90at a more appropriate location.

When the user determines that the clipping device 100 is positionedcorrectly, the proximal pressure on the sliding spool 110 may beincreased to continue deployment of the hemostatic clip 90 from the clipassembly 106. FIGS. 16 and 17 show respectively a top and side view ofthe clipping device 100 in this condition. As the proximal tension onsliding spool 110 is increased, the control cable 118 pulls the yoke 204proximally, away from the tension member 206. The tension member 206 isfirmly attached to the clip arms 208 which are prevented from movingproximally by the interaction of the CSS 222 with the folded tabs 220.If sufficient pulling force is applied to the yoke 204, the male Csection 214 of the tension member 206 yields and loses integrity withthe female C section 216 of the yoke 204. This can occur because, in theexemplary embodiment, the tension member 206 is formed of a materialwith a lower yield strength than the material of the yoke 204.

The force required to break the tension member 206 away from the yoke204 may be tailored to achieve a desired feedback that can be perceivedby the user. The minimum force required to break the tension member 206free of the yoke 204 may be selected so that a tactile feedback is feltby the user, to prevent premature deployment of the hemostatic clip 90while a maximum force may be selected so that other components of thelinkage between the sliding spool 110 and the clip arms 208 do not failbefore the male C section 214 and the female C section 216 disconnectfrom one another. In one exemplary embodiment, the tension forcenecessary to disconnect the two components may be in the range ofapproximately 4 lbf to about 12 lbf. This range may vary depending onthe size of the device and the specific application. To obtain thisforce at the interface of the male and female C sections 214, 216 alarger force will be applied by the user at the sliding spool 110, sincefriction within the device may cause losses along the long flexibleshaft.

When the male C section 214 of tension member 206 yields, several eventstake place within the device 100 nearly simultaneously. Morespecifically, the yoke 204 is no longer constrained from movingproximally by the CSS 222 abutting the capsule 200. Thus the yoke 204travels proximally until coming to rest against a distal bushingshoulder 250. The tension member 206 is not affected by this movementsince it is no longer connected to the yoke 204. The proximal ends 252of the clip arms 208 are normally biased away from a center line of thedevice 100 and are no longer constrained by the yoke overhangs 254.Accordingly, the clip latches 302 are free to engage the latch windows304 of the capsule 200, thus maintaining the integrity of thecapsule-clip arms combination after deployment. Details of the capsule200 are shown in FIGS. 14, 15 and details of the clip arms 208 are shownin FIGS. 18, 19 and 20.

As the yoke 204 moves proximally to abut against the bushing 202, thecapsule tabs 306 are bent away from the centerline of the capsule 200 bythe cam surfaces of the yoke 204. As a result, the capsule tabs 306 areno longer engaged to the corresponding bushing undercuts 350, shown inthe side and perspective views of the bushing 202 depicted in FIGS. 21,22. Since the capsule 200 and the bushing 202 (which is securelyconnected to shaft section 104) are no longer connected, the clipassembly 106 is prevented from being released from the shaft section 104only by its connection to the ball 140 of the control wire 118.

A further result of moving the yoke 204 against the distal bushingshoulder 250 of the bushing 202 is that the distal end of the wire stop360 (shown in FIGS. 12, 16) is placed near the proximal bushing shoulder364 (shown in FIG. 22). The flared fingers 362 located at the distal endof the wire stop 360, better shown in FIG. 23, are compressed as theypass through the central ID of the bushing 202, but return to theirnormally biased open position (shown in FIG. 23) after passing past theproximal bushing shoulder 364. Further distal movement of the slidingspool 110 is thus prevented since that movement would engage the fingers362 of the wire stop 360 with the proximal bushing shoulder 364. Thisfeature prevents the clip assembly 106 from being pushed away from thebushing 202 before the ball 140 is separated from the control wire 118,as will be described below.

The wire stop 360 comprises a tube with a first slotted and flared endattached to the control wire 118 by conventional means. As shown in FIG.23, the slots impart flexibility to the device so it can easily passthrough the central lumen of the bushing 202. Flared fingers 362 areformed by the slots, and engage the proximal bushing shoulder 364. Thewire stop 360 is made of a material that is biocompatible and that hasenough resilience so that the fingers 362 re-open after passage throughthe bushing 202. For example, stainless steel may be used for thisapplication.

One feature of the exemplary embodiment of the invention described aboveis that the user receives both tactile and auditory feedback as the clipassembly 106 is deployed and released. The separation of the tensionmember 206 from the yoke 204 produces a small clicking noise and atactile feel that is perceptible while holding the handle assembly 102.The change in axial position of the sliding spool 110 is thus augmentedby the changes in resistance to its movement and by the clicking soundand feel through the start and stop of the movement. As a result theuser is always aware of the status of the clip assembly 106, and theinadvertent deployment of a hemostatic clip 90 in an incorrect locationis made less likely. It will be apparent to those of skill in the artthat the order of male and female connectors in the device may bereversed or changed without affecting the operation of the device.

It may be beneficial for the user to be certain that the clip assembly106 has been deployed before the rest of the clipping device 100 isremoved from the endoscope. Injury to the tissue being treated couldresult if the clipping device 100 is removed from the operative sitewhen the hemostatic clip 90 is only partially deployed. Accordingly, alarge tactile feedback may be incorporated, to augment the auditory andtactile feedback stemming from the separation of the yoke 204 from thetension member 206. FIG. 24 depicts the condition where the clipassembly 106 separates from the rest of the clipping device 100.According to the described embodiment, this second user feedback isobtained by designing the control wire 118 so that it will separate fromthe end ball 140 when a predetermined tension is applied to it. In otherwords, the ball 140 of the control wire 118 is mechanically programmedto yield and separate from the body of the control wire 118 when apre-set tension is applied thereto. The size of the reduced diametersection 142 can be selected so that, when the user continues to move thesliding spool 110 proximally as the programmed yield tension is reached,the ball 140 detaches from the tapered section 144 and provides a largetactile feedback to the operator.

When the ball 140 detaches, the sliding spool 110 bottoms out at theproximal end of the handle 108, such that a full stroke of the handleassembly 102 is reached. The tension required to cause the reduceddiameter section 142 to yield and release the ball 140 may vary over arange of values. However, for best results the force should be greaterthan the tension force required for the male C section member 214 toseparate from the yoke 204. If this condition is not satisfied, asituation may occur where the clip assembly 106 is locked in place onthe patient's tissue, but cannot be released from the clipping device100. It will be apparent that this situation should be avoided. In oneexemplary embodiment, the tension force required to separate the ball140 from the body of the control wire 118 is in the range of betweenabout 10 lbf and 20 lbf at the distal end of the control wire 118. Asdiscussed above, losses along the elongated flexible shaft may requirethe user to apply a force substantially greater than this to the handlebody 102.

Once the ball 140 has separated from the rest of the control wire 118,the user can pull the rest of the clipping device 100 from theendoscope. As this is done, the yoke 204 is retained within the capsule200 by the spring and frictional forces of the capsule tabs 306. Priorto withdrawing the clipping device 100, the over-sheath 150 may be moveddistally by the user over the entire remaining portions of the shaftsection 104 to prevent damage to the endoscope as the clipping device100 is withdrawn therethrough. The sheath stop 156 may also be placed onthe shaft section 104 proximally of the over-sheath grip 152 to preventinadvertent sliding of the over-sheath 150 from the distal end of thedevice 100.

A more detailed description of several components of the clipping device100 follows. The clip arms 208 are shown in detail in FIGS. 18, 19 and20; the tension member 206 is shown in side and top views in FIGS. 25,26; while top and side views of the yoke 204 are shown respectively inFIGS. 27 and 28. the clip arms 208 may be formed of a biocompatiblematerial such as Nitinol, Titanium or stainless steel. Maximum springproperties may be obtained by using materials such as 400 seriesstainless or 17-7 PH. As shown, a tear drop keyway 400 is formed in theclip arm 208 to mate with a corresponding tear drop key 402 formed onthe tension member 206. This feature maintains the relative positions ofthese two components and of the yoke 204 substantially constant. Theshape of the keyways 400 may be varied. For example, the keyway 400 maybe oval or elliptical. Central portions of the clip arms 208 define aspring section 404. When the proximal ends 252 of the clip arms 208 areunder the yoke overhangs 254, the clip arms 208 are allowed to pivotover the tension member 206, which in turn biases the distal ends 252towards the open configuration when no longer restrained by the capsule200. As a result, the proximal end 252 of each clip arm 208 springsupward and engages the latch windows 304 in the capsule 200.

the clip arms 208 also comprise a radius section 300 that adds strengthto the clip and reduces system friction. The radius of the radiussection 300 approximately matches the inner diameter of the capsule 200and has a smooth profile to avoid scratching the inner surface of thecapsule 200. A pre-load angle α is defined between the radius section300 and the spring section 404. The pre-load angle α determines how muchinterference (pre-load) exists between the two opposing clip arms 208 attheir distal ends when closed. The greater the pre-load angle α, thegreater the engaging force that is applied by the clip arms 208.However, this condition also causes the greatest system friction whenthe hemostatic clip 90 is closed. The clip arms 208 also compriseinterlocking teeth 408 disposed at their distal ends. In the exemplaryembodiment, the teeth 408 are identical so that the arms may beinterchangeable and will mesh smoothly with the set facing them. Theteeth 408 are disposed at a nose angle β which may be betweenapproximately 90 and 135 degrees, but in other applications may begreater or lesser than the described range.

The capsule 200 is shown in detail in FIGS. 14 and 15 and comprisesalignment keyways 500 that are designed to mate with correspondingfeatures on the bushing 202 to rotationally align the two components.The capsule tabs 306 may be bent towards the centerline of the capsule200 to engage the bushing undercuts 350. The engagement maintains theintegrity between the capsule assembly 200 and the rest of the clippingdevice 100 until the yoke is pulled into the distal bushing shoulder.the capsule overhangs 502 provide added clamping strength to thedeployed clip arms 208. This is achieved by reducing the length of theportion of each clip arm 208 that is not supported by a portion of thecapsule 200. This feature does not affect the amount of tissue that maybe captured by the clip arms 208 since the capsule overhangs 502 extendon a plane substantially parallel to the plane of the clip arms 208.

Additional features of the capsule 200 include an assembly aid portwhich may be used to assist in aligning the components of the clipassembly 106. Bending aids 506 facilitate a smooth bend when the distalfolding tabs 220 are bent inward, as described above. The bending aids506, as shown, are holes aligned with the folding line of the tabs 220,but may also include a crease, a linear indentation, or other type ofstress concentrator. The capsule 200 may be formed from any of a varietyof biocompatible materials. For example, stainless steel, Titanium orNitinol or any combination thereof may be used. High strength polymerslike PEEK™ or Ultem™ may also be used to form the capsule 200, with aheat set treatment being used to adjust positionable elements.

FIGS. 25 and 26 depict additional details of the tension member 206. Asshown, tear drop keys 402 are designed to engage the tear drop keyways400 of the clip arms 208, as described above. Clip follower planes 508are shaped to form a fulcrum which allows the clip arms 208 to rockbetween the open and closed configurations. The tension member 206comprises a distal stop face 510 which abuts the distal folding tabs 220of the capsule 200 to stop the distal motion of the capsule assembly106. In general, all surfaces and edges of the tension member 206 thatare in contact with the inner surfaces of the capsule 200 preferablyhave a radius substantially similar to an inner radius of the capsule200 to provide a sliding fit therein. The tension member 206 may beformed of a biocompatible polymer, monomer or thermoset. The type ofmechanism selected to release the tension member 206 from the yoke 204may determine the type of material used since a release due to fractureof the male C section 214 requires a relatively brittle material whilerelease due to yielding without fracture calls for a softer material.

Additional details of the yoke 204 are shown in FIGS. 27-29. When thecontrol wire 118 is seated in the yoke 204, it is desirable to ensurethat it cannot inadvertently be removed from the control wire slot 600.Accordingly, in the present embodiment the ball cavity 602 has adiameter sufficiently large to allow the ball 140 to pass therethroughwhile the wire cavity 604 is large enough to allow the control wire 118to pass therethrough, but not large enough to allow the ball 140 passtherethrough. To assemble the control wire 118 with the yoke 204according to the exemplary embodiment, the proximal end of wire 140 isinserted into the ball cavity 602 until the ball bottoms out, and thenthe control wire 118 is rotated until it is seated in the control wirecavity 604, thus constraining further movement of the ball 140.According to the present embodiment, the yoke 204 may be made of abiocompatible metal such as stainless steel or a high strength polymersuch as Ultem™.

According to embodiments of the present invention, the clipping device100 may be scaled to fit the requirements of different surgicalprocedures. In one exemplary embodiment, the clipping device 100 may besized to fit through an endoscope having a working channel diameter ofapproximately 0.110 inches. The exemplary bushing may have a length ofabout 0.22 inches and an OD of approximately 0.085 inches. The capsulemay have a length of about 0.5 inches, an OD of about 0.085 inches, anda wall thickness of about 0.003 inches. When assembled, the rigid lengthof the capsule 200 and the bushing 202 is approximately 0.625 inches.This length is important because if it is too great, the assembly willnot pass through the bends of the flexible endoscope. In the exemplaryclipping device, the outer sheath may have an ID of approximately 0.088inches and an OD of about 0.102 inches. The overall length of theclipping device may be approximately 160 inches, while the tissuegrasping portion of the clip arms 208 may be approximately 0.4 incheslong.

The present invention has been described with reference to specificexemplary embodiments. Those skilled in the art will understand thatchanges may be made in details, particularly in matters of shape, size,material and arrangement of parts without departing from the teaching ofthe invention. For example, different shapes of the yoke, the tensionmember and the bushing may be used, and different attachments of theclip arms and control wire may be employed. Accordingly, variousmodifications and changes may be made to the embodiments withoutdeparting from the broadest scope of the invention as set forth in theclaims that follow. The specifications and drawings are, therefore, tobe regarded in an illustrative rather than a restrictive sense.

1-36. (canceled)
 37. A medical device, comprising: a clip having firstand second arms biased toward an open configuration; a control wireremovably connected to the clip, the control wire configured to controlmovement of the clip between an open configuration and a closedconfiguration; a separable yoke connecting the control wire to the clip,the yoke configured to be separated by a predetermined force applied bythe control wire so that, when the yoke is separated, the control wireuncouples from the clip; an elongated sheath housing the control wire; ahandle coupled to the elongated sheath; and an actuator coupled to thecontrol wire and configured to open the clip arms, close the clip armsand uncouple the clip from the control wire.
 38. The medical device ofclaim 37, further comprising a capsule removably housing a portion ofthe clip therein, wherein movement of the control wire distally causesthe clip to move distally relative to the capsule and move to the openconfiguration.
 39. The medical device of claim 38, wherein movement ofthe control wire proximally causes the clip to move proximally into thecapsule, the proximal movement causing the clip to move to the closedconfiguration wherein the first and second clip arms are drawn towardone another.
 40. The medical device of claim 38, further comprising alocking arrangement provided in the capsule, the locking arrangementbeing configured to lock the clip against the capsule in the closedconfiguration.
 41. The medical device of claim 37, further comprising aspring portion configured to bias the control wire to a desiredposition.
 42. The medical device of claim 5, wherein the spring portionbiases the control wire to a proximal position corresponding to a closedconfiguration of the clip.
 43. The medical device of claim 38, whereinbefore the clip is separated from the control wire, moving the controlwire in a distal direction pushes the clip out of the capsule, openingthe arms.
 44. The medical device of claim 37, wherein when the first andsecond arms are in an open configuration, proximal ends of the first andsecond arms are positioned under the yoke, the yoke constrainingmovement of the first and second arms.
 45. The medical device of claim38, further comprising folding tabs extending from a distal end of thecapsule, the folding tabs being positioned between the first and secondarms to provide a cam surface as the clip extends distally out of thecapsule.
 46. The medical device of claim 37, wherein the yoke is coupledto the control wire.
 47. A method, comprising: advancing to a targetsite within a living body a medical device comprising a clip havingfirst and second arms biased toward an open configuration, the devicefurther comprising a control wire removably connected to the clip and anelongated sheath housing the control wire; actuating an actuator to movethe control wire proximally and distally to open and closed the firstand second clip arms to grasp tissue therebetween; and applying a firstforce to the control wire to sever a joint between the control wire andthe clip, uncoupling the control wire from the clip.
 48. The method ofclaim 47, wherein the joint between the control wire and the clipcomprises a separable yoke, the first force applied to the control wireseparates the yoke.
 49. The method of claim 47, wherein the actuatingstep comprises moving the control wire proximally to cause the clip tomove proximally into a capsule removably housing a portion of the cliptherein, and causing the clip to move to a closed configuration whereinthe first and second clip arms are drawn toward one another.
 50. Themethod of claim 49, further comprising locking the clip against thecapsule in the closed configuration,
 51. The method of claim 48, whereinwhen the first and second arms are in an open configuration, proximalends of the first and second arms are positioned under the yoke, theyoke constraining movement of the first and second arms.